The present invention relates generally to mint flavors. More specifically, the present invention relates to methods for refining mint flavors and using same in chewing gum.
It is known in the chewing gum industry to add mint flavoring to chewing gum. For example, it is known to add peppermint oil to chewing gum. In addition to adding desirable taste characteristics to the chewing gum, such mint flavoring can add perceived breath freshening properties.
A number of mint flavored chewing gums, however, have a tendency to produce bitter flavor notes in the latter part of a chew. This is due, in part, to the fact that most, if not all, of the sweetness properties have been dissipated. This causes more of the mint flavor to become apparent, as well as the bitterness.
One method for reducing bitterness is disclosed in U.S. Pat. No. 5,372,824, entitled: xe2x80x9cMINT FLAVORED CHEWING GUM HAVING REDUCED BITTERNESS AND METHODS FOR MAKING SAME.xe2x80x9d In that patent, a method is provided for producing mint flavored chewing gums having reduced bitterness. In part, that patent discloses a chewing gum including a water insoluble base portion, a water soluble portion, and a mint flavor agent from which at least a portion of 1-menthol has been removed.
Other patents and patent applications have considered modifying the formulation of chewing gum to deal with the undesirable properties of mint flavoring. These patents and published PCT patent applications include: U.S. Pat. Nos. 4,948,595; 4,889,726; 5,041,294; 5,128,154; 4,708,880; 4,980,169; 4,613,513; PCT 90-006689; and PCT 91-00547.
Another issue raised by mint flavor oils, such as peppermint oil, is that initially they typically include sulfur containing compounds such as dimethyl sulfide. In attempting to create a more palatable peppermint oil, usually, peppermint oil compositions are distilled to remove dimethyl sulfide and other sulfur compounds. Typically, distillations of peppermint oil are performed by steam distillation. However, such distillation processes are not entirely satisfactory.
U.S. Pat. No. 5,425,962 discloses the use of vacuum distillation to remove dimethyl sulfide.
Typically peppermint oil contains menthofuran. Menthofuran reduces palatability. Peppermint oil comprises about 1-8% menthofuran which has a tendency to oxidize and polymerize which will lower the quality of the mint oil.
Peppermint oils that contain high levels of menthofuran are considered lower in quality, whereas peppermint oils that are low in menthofuran are considered high quality oils. Menthofuran adds a distinctive heavy diesel flavor note to mint oils that is not desirable.
The typical steam distillation process in addition to removing sulfur containing components also removes desirable low boiling point peppermint oil components. For example, 3-methylbutanal is a desirable component of most peppermint flavors; 3-methylbutanal imparts creamy, chocolate notes to the flavor. Due to its low boiling point, steam distillation also removes 3-methylbutanal in addition to other desirable components. Typical steam distillation also does not remove menthofuran.
An additional problem with most currently used methods of refining peppermint oil is that they may subject the peppermint oil to excessive heat history. This can produce undesirable changes in the flavor; for example, excessive distillation can create still notes.
Further, steam distillation leaves substantial quantities of water in the flavor. This water must be removed. This adds a further step to the distillation process.
There is therefore a need for an improved method for refining peppermint oil to remove dimethyl sulfide and menthofuran.
The present invention provides improved methods for refining peppermint oil containing compositions. Additionally, the present invention provides improved methods for making chewing gum having a peppermint flavor.
To this end, a method for refining a peppermint oil containing composition that includes sulfur compounds to remove at least a portion of the sulfur compounds is provided. The method comprises the step of subjecting the composition to a distillation process that removes at least 50% of the menthofuran contained in the peppermint oil.
In an embodiment, less than 15% of peppermint oil composition is removed which contains both sulfur compounds and menthofuran.
In an embodiment, the composition consists essentially of peppermint oil. In an embodiment, more than 0.25% of the composition that contain sulfur compounds is removed by the distillation process.
In a further embodiment, the pressure during the vacuum distillation process is reduced to no more than 150 mmHg.
In a further embodiment, the temperature of the composition during the distillation process does not exceed 120xc2x0 C.
In an embodiment, after the distillation process, the composition includes not more than 75 ppm dimethyl sulfide.
In an embodiment, after the distillation process, the composition includes not more than 2% menthofuran.
In an embodiment, the method includes the step of agitating a distillation pot including the composition during the distillation process.
In an embodiment, the method includes the step of blanketing a distillation pot including the composition with an inert gas during the distillation process.
In an embodiment, the level of 3-methylbutanal in the composition after distillation is not reduced below 100 ppm.
The present invention also provides a method for creating a peppermint flavor chewing gum comprising the steps of adding to an insoluble gum base portion and a water soluble portion a peppermint oil that has been refined by subjecting a peppermint oil containing composition to a vacuum distillation process for a sufficient time and at sufficient parameters to achieve at least approximately 50% reduction of the menthofuran in the peppermint oil.
In an embodiment, the present invention provides a method for refining peppermint oil comprising the steps of subjecting a peppermint oil containing composition to a vacuum distillation process wherein the pressure is reduced to less than or equal to 150 mmHg and the composition is not subjected to a temperature greater than 140xc2x0 C. and removing during the process sufficient dimethyl sulfide that may be present to provide a refined peppermint oil having a dimethyl sulfide content of less than 75 ppm and a menthofuran content of less than 2%.
An advantage of the present invention is that it provides an improved method for refining mint oil, such as peppermint oil.
Another advantage of the present invention is that it provides a method for providing refined peppermint oil for use in creating chewing gum.
Furthermore, an advantage of the present invention is that it provides a method for creating mint flavored chewing gum.
Additionally, an advantage of the present invention is that it provides an improved peppermint flavored chewing gum.
Additional features and advantages of the present invention are described in, and will be apparent from, the detailed description of the presently preferred embodiments and from the drawings.
The present invention provides an improved method for refining peppermint oil and peppermint oil containing-compositions. Additionally, the present invention provides an improved method for making chewing gum including peppermint oil.
Pursuant to the present invention, a method is provided for refining peppermint oil and peppermint oil blends to remove sulfur compounds and menthofuran, while returning desirable low boiling point components to the undistilled fraction. Although, in an embodiment of the present invention, the peppermint oil can be used in the production of chewing gum, the present invention will have applications to the production of other mint flavored products, such as mint flavored confectionery products.
The present invention can be used to refine not only compositions that consist essentially of peppermint oil, but compositions that include a blend of peppermint oil and other flavors or mint oils. In this regard, the peppermint oil composition may include other flavors, such as spearmint oil.
Pursuant to the present invention, a method for refining peppermint oil, or peppermint oil blends, to remove sulfur components and menthofuran is provided comprising the step of subjecting the flavor to a distillation. Preferably, a batch vacuum distillation process is used.
Using the vacuum process, the vacuum distillation is performed at relatively low temperatures over a short period of time to remove the first approximate 0.25% to about 3% of the distillate, preserving the monoterpenes distilled off between the dimethyl sulfide and menthofutan and removing a significant portion of menthofuran. In a preferred embodiment, not more than 2% of the first distillate is removed. As the vacuum distillation process continues, desirable monoterpenes and low molecular weight low boilers such as 3-methylbutanal are removed. This low boiler distillate is about 8-15% of the peppermint oil and is removed and reserved. Continued distillation will then remove menthofuran in the next 2-10% of the next distillate and can be discarded. At this point the vacuum distillation can be stopped and the remaining 75-90% of non-distilled peppermint oil can be combined with the reserved low boiler distillate to obtain a rectified or refined natural peppermint oil.
The refined oil will have a reduced menthofuran level. If a high menthofuran peppermint oil such as 5-8% weight was distilled, then the level will be reduced to less than about 2.5-4% weight. If a low menthofuran peppermint oil, such as 1-3% weight, was distilled, the menthofuran level will be reduced to less than about 0.5 to 1.5% weight. At least 50% of the menthofuran can be removed by vacuum distillation after the low boilers are removed. Continued distillation results in removal of the menthofuran fraction, and then recombining the low boiling fraction with the remaining undistilled peppermint fraction.
During the distillation process, a vacuum is created that reduces the pressure during the process to less than or equal to 150 mmHg. Preferably, it has been found that the pressure should be reduced to less than 100 mm and most preferably, less than 60 mmHg. However, in a most preferred embodiment, the pressure is reduced to less than or equal to 30 mmHg. In a further preferred embodiment, the pressure is reduced to less than or equal to 15 mmHg.
During the distillation process, in order to prevent degradation of the flavor components while insuring efficient distillation, the temperature of the oil being distilled should not exceed approximately 140xc2x0 C. Preferably, the temperature of the oil will not exceed approximately 100xc2x0 C. for any extended period of time. However, it should be noted that it is acceptable for the temperature to briefly, e.g., less than approximately 50% of the total distillation time, exceed these temperatures before cooling procedures are initiated to prevent thermal degradation.
It is believed that separation effectiveness is necessary to practice the vacuum distillation of the present invention. It is possible that fractionating columns or other apparatuses having at least 3-4 theoretical plates are needed to be effective. Of course, columns with more theoretical plates can also be used.
The distillation pot containing the oil to be refined should be agitated during the process. This will prevent degradation that can be caused by uneven heating and other problems. A number of means can be used for agitating the distillation pot. Such means include using mechanically or magnetically driven impellers or bubbling inert gas into the oil. Other means, however, can also be used.
In an embodiment, to reduce oxidation which can occur during the distillation process, the distillation pot can be blanketed with an inert gas, such as nitrogen. This is especially useful when the vessel is repressurized after completing the distillation.
In performing the process of the present invention using stills having an adjustable reflux apparatus, the reflux setting will be determined by the characteristics of the distillation apparatus being used. With some equipment, it may be desirable to set the reflux to a high return ratio until the desired starting temperature and pressure are reached. However, the apparatus will normally be set to a high collection ratio once the distillation process begins.
As previously noted, typically, dimethyl sulfide is present in peppermint oil at levels from 100 to 1,000 ppm (parts per million by weight). In an embodiment, the first portion of the vacuum distillation process can be run until the undistilled portion includes less than 75 ppm of dimethyl sulfide. It has been determined, through sensory testing, that peppermint oil having levels of dimethyl sulfide greater than 75 ppm are negatively perceived by experienced judges as compared to peppermint oil having less than 75 ppm dimethyl sulfide.
As noted above, one desirable constituent that imparts creamy, chocolate notes to the peppermint flavor is 3-methylbutanal. This compound normally occurs in peppermint oil, prior to any refining process, at levels of approximately 400 to about 1,000 ppm by weight. The distillation process of the present invention should not reduce the level of this component below 100 ppm and preferably, not below 200 ppm. Indeed, it has been found that the method of the present invention can create refined peppermint oil including 3-methylbutanal at a level of 250 ppm or greater.
To determine the end point of the first portion of the distillation process, a variety of methods can be used. One method is to use a sulfur detector in the distillation pot to directly measure dimethyl sulfide levels. When the desired reduction in dimethyl sulfide is reached, the collected distillate is removed and discarded and the distillation process is continued.
If desired, a number of trial distillations can be used to determine how much distillate should be collected in the receiver to achieve the desired reduction of dimethyl sulfide while maintaining high levels of 3-methylbutanal. These trial distillations should also give the amount of distillation to obtain the low boiler distillate and the menthofuran distillate. The amount of distillate that must be collected will probably vary with the design and scale of the equipment used, as well as the initial dimethyl sulfide level and menthofuran level and to a lesser extent, the amount of water in the undistilled flavor. It may also desirable to establish a steady state condition in the still by running at least one or two batches to wet the initial surfaces of the distillation apparatus.
Pursuant to the present invention, a good quality peppermint oil will yield 90% to 97% refined oil in a steady state batch process. In addition to the distillate removed, losses may include material loss to the vacuum pump and trap and other equipment areas. Additionally, in the first batch or two, material used to wet the internal surfaces of the distillation apparatus will also be lost.